Commit Graph

3934 Commits

Author SHA1 Message Date
Manuel Pégourié-Gonnard
6346a75dfb Merge branch 'development' into iotssl-1260-non-blocking-ecc-restricted
* development:
  ssl-opt.sh: change expected output for large srv packet test with SSLv3
  Adapt ChangeLog
  Fix bug in SSL ticket implementation removing keys of age < 1s
  ssl-opt.sh: Add DTLS session resumption tests
  Add ChangeLog entry
  Fix typo
  Fix hmac_drbg failure in benchmark, with threading
  Remove trailing whitespace
  Remove trailing whitespace
  ssl_server2: add buffer overhead for a termination character
  Add missing large and small packet tests for ssl_server2
  Added buffer_size and response_size options for ssl-server2. Added appropriate tests.

Solving a conflict in tests/ssl-opt.sh: two set of tests were added at the
same place (just after large packets):
- restartable ECC tests (in this branch)
- server-side large packets (in development)

Resolution was to move the ECC tests after the newly added server large packet
ones.
2018-10-15 11:26:17 +02:00
Gilles Peskine
4899247bf2 Fix undefined behavior in unsigned-to-signed conversion
The code assumed that `int x = - (unsigned) u` with 0 <= u < INT_MAX
sets `x` to the negative of u, but actually this calculates
(UINT_MAX - u) and then converts this value to int, which overflows.
Cast to int before applying the unary minus operator to guarantee the
desired behavior.
2018-10-12 20:32:55 +02:00
Gilles Peskine
9b430704d1 Fix likely-harmless undefined behavior surrounding volatile
The code was making two unsequenced reads from volatile locations.
This is undefined behavior. It was probably harmless because we didn't
care in what order the reads happened and the reads were from ordinary
memory, but UB is UB and IAR8 complained.
2018-10-12 20:32:52 +02:00
Hanno Becker
805f2e11bd Add missing zeroization of buffered handshake messages
This commit ensures that buffers holding fragmented or
future handshake messages get zeroized before they are
freed when the respective handshake message is no longer
needed. Previously, the handshake message content would
leak on the heap.
2018-10-12 16:50:37 +01:00
Andrzej Kurek
748face36f ssl_tls: fix maximum output length
set maximum output length to MBEDTLS_SSL_OUT_CONTENT_LEN instead of
MBEDTLS_SSL_MAX_CONTENT_LEN.
2018-10-11 07:20:19 -04:00
Hanno Becker
780f0a4cc1 Reinitialize PK ctx in mbedtls_pk_parse_key before reuse are free
Context: This commit makes a change to mbedtls_pk_parse_key() which
is responsible for parsing of private keys. The function doesn't know
the key format in advance (PEM vs. DER, encrypted vs. unencrypted) and
tries them one by one, resetting the PK context in between.

Issue: The previous code resets the PK context through a call to
mbedtls_pk_free() along, lacking the accompanying mbedtls_pk_init()
call. Practically, this is not an issue because functionally
mbedtls_pk_free() + mbedtls_pk_init() is equivalent to mbedtls_pk_free()
with the current implementation of these functions, but strictly
speaking it's nonetheless a violation of the API semantics according
to which xxx_free() functions leave a context in uninitialized state.
(yet not entirely random, because xxx_free() functions must be idempotent,
so they cannot just fill the context they operate on with garbage).

Change: The commit adds calls to mbedtls_pk_init() after those calls
to mbedtls_pk_free() within mbedtls_pk_parse_key() after which the
PK context might still be used.
2018-10-11 11:31:15 +01:00
Hanno Becker
cfa2e33fd2 Omit runtime configuration of calloc/free if macro config enabled
This commit removes the definition of the API function

`mbedtls_platform_set_calloc_free()`

from `library/platform.c` in case the macros

`MBEDTLS_PLATFORM_CALLOC_MACRO`
`MBEDTLS_PLATFORM_FREE_MACRO`

for compile time configuration of calloc/free are set.

This is in line with the corresponding header `mbedtls/platform.h`
which declares `mbedtls_platform_set_calloc_free()` only if
`MBEDTLS_PLATFORM_{CALLOC/FREE}_MACRO` are not defined.

Fixes #1642.
2018-10-11 11:04:20 +01:00
Hanno Becker
8df10232cf Add explicit unsigned-to-signed integer conversion
The previous code triggered a compiler warning because of a comparison
of a signed and an unsigned integer.

The conversion is safe because `len` is representable by 16-bits,
hence smaller than the maximum integer.
2018-10-10 15:48:39 +01:00
Darryl Green
e3f95ed25b Fix bias in random number generation in Miller-Rabin test
When a random number is generated for the Miller-Rabin primality test,
if the bit length of the random number is larger than the number being
tested, the random number is shifted right to have the same bit length.
This introduces bias, as the random number is now guaranteed to be
larger than 2^(bit length-1).

Changing this to instead zero all bits higher than the tested numbers
bit length will remove this bias and keep the random number being
uniformly generated.
2018-10-09 16:36:53 +01:00
Janos Follath
a0b67c2f3e Bignum: Deprecate mbedtls_mpi_is_prime()
When using a primality testing function the tolerable error rate depends
on the scheme in question, the required security strength and wether it
is used for key generation or parameter validation. To support all use
cases we need more flexibility than what the old API provides.
2018-10-09 16:36:53 +01:00
Janos Follath
da31fa137a Bignum: Fix prime validation vulnerability
The input distribution to primality testing functions is completely
different when used for generating primes and when for validating
primes. The constants used in the library are geared towards the prime
generation use case and are weak when used for validation. (Maliciously
constructed composite numbers can pass the test with high probability)

The mbedtls_mpi_is_prime() function is in the public API and although it
is not documented, it is reasonable to assume that the primary use case
is validating primes. The RSA module too uses it for validating key
material.
2018-10-09 16:36:53 +01:00
Janos Follath
b728c29114 Bignum: Remove dead code
Both variables affected by the code are overwritten before their next
read.
2018-10-09 16:33:27 +01:00
Janos Follath
b8fc1b02ee RSA: Use MBEDTLS_MPI_GEN_PRIME_FLAG_LOW_ERR 2018-10-09 16:33:27 +01:00
Janos Follath
f301d23ceb Bignum: Improve primality test for FIPS primes
The FIPS 186-4 RSA key generation prescribes lower failure probability
in primality testing and this makes key generation slower. We enable the
caller to decide between compliance/security and performance.

This python script calculates the base two logarithm of the formulas in
HAC Fact 4.48 and was used to determine the breakpoints and number of
rounds:

def mrpkt_log_2(k, t):
    if t <= k/9.0:
        return 3*math.log(k,2)/2+t-math.log(t,2)/2+4-2*math.sqrt(t*k)
    elif t <= k/4.0:
        c1 = math.log(7.0*k/20,2)-5*t
        c2 = math.log(1/7.0,2)+15*math.log(k,2)/4.0-k/2.0-2*t
        c3 = math.log(12*k,2)-k/4.0-3*t
        return max(c1, c2, c3)
    else:
        return math.log(1/7.0)+15*math.log(k,2)/4.0-k/2.0-2*t
2018-10-09 16:33:27 +01:00
Andrzej Kurek
ef43ce6e25 Dtls: change the way unlimited mtu is set for client hello messages 2018-10-09 08:24:12 -04:00
Hanno Becker
1624e2e8bb Avoid overly long lines X.509 DN attr array def in x509_create.c 2018-10-08 14:52:20 +01:00
Hanno Becker
35b6854e54 Replace reference to RFC 3280 by reference to newer RFC 5280 2018-10-08 14:47:38 +01:00
Hanno Becker
cfc47bab69 Correct some indentation and line lengths in x509_create.c 2018-10-08 14:45:42 +01:00
Hanno Becker
d355e69aed Rename tag to default_tag in x509_attr_descriptor_t 2018-10-08 14:44:32 +01:00
Hanno Becker
d2c9009e5a Improve documentation of x509_attr_descriptor_t 2018-10-08 14:42:34 +01:00
Hanno Becker
0c161d1956 Fix bounds check in ssl_parse_server_psk_hint()
In the previous bounds check `(*p) > end - len`, the computation
of `end - len` might underflow if `end` is within the first 64KB
of the address space (note that the length `len` is controlled by
the peer). In this case, the bounds check will be bypassed, leading
to `*p` exceed the message bounds by up to 64KB when leaving
`ssl_parse_server_psk_hint()`. In a pure PSK-based handshake,
this doesn't seem to have any consequences, as `*p*` is not accessed
afterwards. In a PSK-(EC)DHE handshake, however, `*p` is read from
in `ssl_parse_server_ecdh_params()` and `ssl_parse_server_dh_params()`
which might lead to an application crash of information leakage.
2018-10-08 13:40:50 +01:00
Gilles Peskine
ec2a5fdee1 PKCS#1 v1.5 decoding: fix empty payload case 2018-10-05 20:48:20 +02:00
Gilles Peskine
40b57f4acd Remove a remaining sensitive memory access in PKCS#1 v1.5 decryption 2018-10-05 15:35:03 +02:00
Gilles Peskine
85a7442753 mbedtls_rsa_rsaes_pkcs1_v15_decrypt: remove the variable p
Get rid of the variable p. This makes it more apparent where the code
accesses the buffer at an offset whose value is sensitive.

No intended behavior change in this commit.
2018-10-05 14:50:21 +02:00
Andrzej Kurek
6290dae909 Disable dtls fragmentation for ClientHello messages
Set the handshake mtu to unlimited when encountering a ClienHello message and
reset it to its previous value after writing the record.
2018-10-05 08:06:01 -04:00
Gilles Peskine
eeedabe25e Minor optimization in the PKCS#1v1.5 unpadding step
Rather than doing the quadratic-time constant-memory-trace on the
whole working buffer, do it on the section of the buffer where the
data to copy has to lie, which can be significantly smaller if the
output buffer is significantly smaller than the working buffer, e.g.
for TLS RSA ciphersuites (48 bytes vs MBEDTLS_MPI_MAX_SIZE).
2018-10-04 22:45:13 +02:00
Gilles Peskine
8c9440a2cb Use branch-free size comparison for the padding size
In mbedtls_rsa_rsaes_pkcs1_v15_decrypt, use size_greater_than (which
is based on bitwise operations) instead of the < operator to compare
sizes when the values being compared must not leak. Some compilers
compile < to a branch at least under some circumstances (observed with
gcc 5.4 for arm-gnueabi -O9 on a toy program).
2018-10-04 21:44:40 +02:00
Gilles Peskine
a1af5c8ea2 Bleichenbacher fix: don't leak the plaintext length (step 2)
Replace memmove(to, to + offset, length) by a functionally equivalent
function that strives to make the same memory access patterns
regardless of the value of length. This fixes an information leak
through timing (especially timing of memory accesses via cache probes)
that leads to a Bleichenbacher-style attack on PKCS#1 v1.5 decryption
using the plaintext length as the observable.
2018-10-04 21:44:29 +02:00
Gilles Peskine
9265ff4ee6 Bleichenbacher fix: don't leak the plaintext length (step 1)
mbedtls_rsa_rsaes_pkcs1_v15_decrypt takes care not to reveal whether
the padding is valid or not, even through timing or memory access
patterns. This is a defense against an attack published by
Bleichenbacher. The attacker can also obtain the same information by
observing the length of the plaintext. The current implementation
leaks the length of the plaintext through timing and memory access
patterns.

This commit is a first step towards fixing this leak. It reduces the
leak to a single memmove call inside the working buffer.
2018-10-04 21:38:22 +02:00
Gilles Peskine
331d80e162 Evolve choose_int_from_mask to if_int
Make the function more robust by taking an arbitrary zero/nonzero
argument instead of insisting on zero/all-bits-one. Update and fix its
documentation.
2018-10-04 21:36:34 +02:00
Simon Butcher
d2642584cb Make inclusion of stdio.h conditional in x509_crt.c
stdio.h was being included both conditionally if MBEDTLS_FS_IO was
defined, and also unconditionally, which made at least one of them
redundant.

This change removes the unconditional inclusion of stdio.h and makes it
conditional on MBEDTLS_PLATFORM_C.
2018-10-03 15:11:19 +01:00
Gilles Peskine
e2a10de275 Fix a timing-based Bleichenbacher attack on PKCS#1v1.5 decryption
mbedtls_rsa_rsaes_pkcs1_v15_decrypt took care of calculating the
padding length without leaking the amount of padding or the validity
of the padding. However it then skipped the copying of the data if the
padding was invalid, which could allow an adversary to find out
whether the padding was valid through precise timing measurements,
especially if for a local attacker who could observe memory access via
cache timings.

Avoid this leak by always copying from the decryption buffer to the
output buffer, even when the padding is invalid. With invalid padding,
copy the same amount of data as what is expected on valid padding: the
minimum valid padding size if this fits in the output buffer,
otherwise the output buffer size. To avoid leaking payload data from
an unsuccessful decryption, zero the decryption buffer before copying
if the padding was invalid.
2018-10-03 01:03:05 +02:00
Gilles Peskine
5908dd4455 Minor readability improvement
Polish the beginning of mbedtls_rsa_rsaes_pkcs1_v15_decrypt a little,
to prepare for some behavior changes.
2018-10-02 22:43:06 +02:00
Jaeden Amero
3725bb2d6d rsa: pss: Enable use of big hashes with small keys
It should be valid to RSASSA-PSS sign a SHA-512 hash with a 1024-bit or
1032-bit RSA key, but with the salt size being always equal to the hash
size, this isn't possible: the key is too small.

To enable use of hashes that are relatively large compared to the key
size, allow reducing the salt size to no less than the hash size minus 2
bytes. We don't allow salt sizes smaller than the hash size minus 2
bytes because that too significantly changes the security guarantees the
library provides compared to the previous implementation which always
used a salt size equal to the hash size. The new calculated salt size
remains compliant with FIPS 186-4.

We also need to update the "hash too large" test, since we now reduce
the salt size when certain key sizes are used. We used to not support
1024-bit keys with SHA-512, but now we support this by reducing the salt
size to 62. Update the "hash too large" test to use a 1016-bit RSA key
with SHA-512, which still has too large of a hash because we will not
reduce the salt size further than 2 bytes shorter than the hash size.

The RSA private key used for the test was generated using "openssl
genrsa 1016" using OpenSSL 1.1.1-pre8.

    $ openssl genrsa 1016
    Generating RSA private key, 1016 bit long modulus (2 primes)
    ..............++++++
    ....++++++
    e is 65537 (0x010001)
    -----BEGIN RSA PRIVATE KEY-----
    MIICVwIBAAKBgACu54dKTbLxUQBEQF2ynxTfDze7z2H8vMmUo9McqvhYp0zI8qQK
    yanOeqmgaA9iz52NS4JxFFM/2/hvFvyd/ly/hX2GE1UZpGEf/FnLdHOGFhmnjj7D
    FHFegEz/gtbzLp9X3fOQVjYpiDvTT0Do20EyCbFRzul9gXpdZcfaVHNLAgMBAAEC
    gYAAiWht2ksmnP01B2nF8tGV1RQghhUL90Hd4D/AWFJdX1C4O1qc07jRBd1KLDH0
    fH19WocLCImeSZooGCZn+jveTuaEH14w6I0EfnpKDcpWVAoIP6I8eSdAttrnTyTn
    Y7VgPrcobyq4WkCVCD/jLUbn97CneF7EHNspXGMTvorMeQJADjy2hF5SginhnPsk
    YR5oWawc6n01mStuLnloI8Uq/6A0AOQoMPkGl/CESZw+NYfe/BnnSeckM917cMKL
    DIKAtwJADEj55Frjj9tKUUO+N9eaEM1PH5eC7yakhIpESccs/XEsaDUIGHNjhctK
    mrbbWu+OlsVRA5z8yJFYIa7gae1mDQJABjtQ8JOQreTDGkFbZR84MbgCWClCIq89
    5R3DFZUiAw4OdS1o4ja+Shc+8DFxkWDNm6+C63g/Amy5sVuWHX2p9QI/a69Cxmns
    TxHoXm1w9Azublk7N7DgB26yqxlTfWJo+ysOFmLEk47g0ekoCwLPxkwXlYIEoad2
    JqPh418DwYExAkACcqrd9+rfxtrbCbTXHEizW7aHR+fVOr9lpXXDEZTlDJ57sRkS
    SpjXbAmylqQuKLqH8h/72RbiP36kEm5ptmw2
    -----END RSA PRIVATE KEY-----
2018-09-27 18:23:08 +01:00
Simon Butcher
c86993e33c Merge remote-tracking branch 'public/pr/1970' into development 2018-09-27 09:48:54 +01:00
Janos Follath
7c025a9f50 Generalize dh_flag in mbedtls_mpi_gen_prime
Setting the dh_flag to 1 used to indicate that the caller requests safe
primes from mbedtls_mpi_gen_prime. We generalize the functionality to
make room for more flags in that parameter.
2018-09-21 16:30:07 +01:00
thomas-dee
eba6c9bb50 changes requested by @hanno-arm
- renamed `mbedtls_asn1_write_any_string` to `mbedtls_asn1_write_tagged_string`
 - renamed `x509_at_oid_from_name` to `x509_attr_descr_from_name`
2018-09-19 09:10:37 +02:00
Ron Eldor
54a7c620bb Minor style changes
1. Rephrase error description.
2. fix alignment of error list.
2018-09-12 14:43:44 +03:00
Manuel Pégourié-Gonnard
1c1c20ed4d Fix some whitespace issues 2018-09-12 10:34:43 +02:00
Jaeden Amero
ff215726b4 rsa: pss: Use size_t when computing signatures
Functions like `mbedtls_md_get_size()` and `mgf_mask()` work with
`size_t`. Use local variables with `size_t` to match.
2018-09-11 14:36:03 +01:00
Manuel Pégourié-Gonnard
125af948c3 Merge branch 'development-restricted' into iotssl-1260-non-blocking-ecc-restricted
* development-restricted: (578 commits)
  Update library version number to 2.13.1
  Don't define _POSIX_C_SOURCE in header file
  Don't declare and define gmtime()-mutex on Windows platforms
  Correct preprocessor guards determining use of gmtime()
  Correct documentation of mbedtls_platform_gmtime_r()
  Correct typo in documentation of mbedtls_platform_gmtime_r()
  Correct POSIX version check to determine presence of gmtime_r()
  Improve documentation of mbedtls_platform_gmtime_r()
  platform_utils.{c/h} -> platform_util.{c/h}
  Don't include platform_time.h if !MBEDTLS_HAVE_TIME
  Improve wording of documentation of MBEDTLS_PLATFORM_GMTIME_R_ALT
  Fix typo in documentation of MBEDTLS_PLATFORM_GMTIME_R_ALT
  Replace 'thread safe' by 'thread-safe' in the documentation
  Improve documentation of MBEDTLS_HAVE_TIME_DATE
  ChangeLog: Add missing renamings gmtime -> gmtime_r
  Improve documentation of MBEDTLS_HAVE_TIME_DATE
  Minor documentation improvements
  Style: Add missing period in documentation in threading.h
  Rename mbedtls_platform_gmtime() to mbedtls_platform_gmtime_r()
  Guard decl and use of gmtime mutex by HAVE_TIME_DATE and !GMTIME_ALT
  ...
2018-09-11 12:39:14 +02:00
Simon Butcher
53546ea099 Update library version number to 2.13.1 2018-09-06 19:10:26 +01:00
Simon Butcher
5d40f67138 Merge remote-tracking branch 'public/pr/1927' into development-restricted 2018-09-06 16:24:48 +01:00
Hanno Becker
f5106d54eb Don't declare and define gmtime()-mutex on Windows platforms 2018-09-06 12:09:56 +01:00
Hanno Becker
323d8019bf Correct preprocessor guards determining use of gmtime()
The previous code erroneously used gmtime_r() to implement
mbedtls_platform_gmtime() in case of a non-windows, non-unix system.
2018-09-06 11:30:57 +01:00
Hanno Becker
6f70581c4a Correct POSIX version check to determine presence of gmtime_r()
Recent versions of POSIX move gmtime_r to the base.
2018-09-06 09:06:33 +01:00
Hanno Becker
7dd82b4f51 platform_utils.{c/h} -> platform_util.{c/h} 2018-09-05 16:26:04 +01:00
Hanno Becker
48a816ff26 Minor documentation improvements 2018-09-05 15:22:22 +01:00
Hanno Becker
6a739789f3 Rename mbedtls_platform_gmtime() to mbedtls_platform_gmtime_r()
For consistency, also rename MBEDTLS_PLATFORM_GMTIME_ALT to
MBEDTLS_PLATFORM_GMTIME_R_ALT.
2018-09-05 15:06:19 +01:00
Hanno Becker
be2e4bddd5 Guard decl and use of gmtime mutex by HAVE_TIME_DATE and !GMTIME_ALT 2018-09-05 14:44:31 +01:00
Hanno Becker
cfeb70c6b9 gmtime: Remove special treatment for IAR
Previous commits attempted to use `gmtime_s()` for IAR systems; however,
this attempt depends on the use of C11 extensions which lead to incompatibility
with other pieces of the library, such as the use of `memset()` which is
being deprecated in favor of `memset_s()` in C11.
2018-09-05 13:52:46 +01:00
Andres Amaya Garcia
94b540ac63 Avoid redefining _POSIX_C_SOURCE 2018-09-05 12:27:32 +01:00
Andres Amaya Garcia
433f911e59 Check for IAR in gmtime macros 2018-09-05 12:01:57 +01:00
Andres Amaya Garcia
3c9733a0a3 Fix typo in comment for gmtime macro defines 2018-09-05 11:52:07 +01:00
Andres Amaya Garcia
ca04a01bb8 Document shorthand gmtime macros 2018-09-05 11:43:57 +01:00
Andres Amaya Garcia
209960611f Use gmtime_s() for IAR 2018-09-05 11:27:56 +01:00
Andres Amaya Garcia
e9b10b21f1 Define _POSIX_C_SOURCE in threading.c before POSIX detection 2018-09-05 11:25:30 +01:00
Simon Butcher
4d075cd7d0 Update library version number to 2.13.0 2018-08-31 15:59:10 +01:00
irwir
da642d98c0
Implicit _endthread call: comment changed 2018-08-31 15:14:54 +03:00
irwir
e1b82ad25f
Added spaces after type casts
`(void) TimerContext;` seems more consistent with the current style than ((void) TimerContext);
No objections to changing this if necessary.
2018-08-30 11:57:09 +03:00
Simon Butcher
0bbb4fc132 Merge branch 'development' into development 2018-08-30 01:11:35 +01:00
Simon Butcher
552754a6ee Merge remote-tracking branch 'public/pr/1988' into development 2018-08-30 00:57:28 +01:00
Simon Butcher
68dbc94720 Merge remote-tracking branch 'public/pr/1951' into development 2018-08-30 00:56:56 +01:00
Ron Eldor
b0ad581526 Remove the invalid input for platform module
Remove the invalid input for the platform module,
as it's not currently used in the Mbed OS platform setup \
termination code.
2018-08-29 19:06:14 +03:00
Ron Eldor
0ff4e0b824 Add platform error codes
Add error codes for the platform module, to be used by
the setup \ terminate API.
2018-08-29 18:53:20 +03:00
Hanno Becker
a591c48302 Correct typo in debug message 2018-08-28 17:52:53 +01:00
Hanno Becker
83ab41c665 Correct typo in comment 2018-08-28 17:52:53 +01:00
Hanno Becker
cd9dcda0a0 Add const qualifier to handshake header reading functions 2018-08-28 17:52:53 +01:00
Hanno Becker
39b8bc9aef Change wording of debug message 2018-08-28 17:52:49 +01:00
Hanno Becker
ef7afdfa5a Rename another_record_in_datagram to next_record_is_in_datagram 2018-08-28 17:16:31 +01:00
Hanno Becker
c573ac33dd Fix typos in debug message and comment in ssl-tls.c 2018-08-28 17:15:25 +01:00
Simon Butcher
3af567d4a7 Merge remote-tracking branch 'restricted/pr/437' into development-restricted 2018-08-28 15:33:59 +01:00
Simon Butcher
129fa82908 Merge remote-tracking branch 'restricted/pr/470' into development-restricted 2018-08-28 15:26:11 +01:00
Simon Butcher
7f85563f9b Merge remote-tracking branch 'restricted/pr/491' into development-restricted 2018-08-28 15:22:40 +01:00
Simon Butcher
9ce5160fea Merge remote-tracking branch 'public/pr/1965' into development 2018-08-28 12:34:14 +01:00
Simon Butcher
9d5a9e1213 Merge remote-tracking branch 'public/pr/1625' into development 2018-08-28 12:23:40 +01:00
Simon Butcher
14dac0953e Merge remote-tracking branch 'public/pr/1918' into development 2018-08-28 12:21:41 +01:00
Simon Butcher
1846e406c8 Merge remote-tracking branch 'public/pr/1939' into development 2018-08-28 12:19:56 +01:00
Simon Butcher
9598845d11 Merge remote-tracking branch 'public/pr/1955' into development 2018-08-28 12:00:18 +01:00
Simon Butcher
4613772dea Merge remote-tracking branch 'public/pr/1915' into development 2018-08-28 11:45:44 +01:00
Hanno Becker
0207e533b2 Style: Correct typo in ssl-tls.c 2018-08-28 10:28:28 +01:00
Hanno Becker
bc2498a9ff Style: Add numerous comments indicating condition guarded by #endif 2018-08-28 10:13:29 +01:00
Hanno Becker
d58477769d Style: Group buffering-related forward declarations in ssl_tls.c 2018-08-28 10:09:23 +01:00
Hanno Becker
360bef3fe3 Reordering: Document that only HS and CCS msgs are buffered 2018-08-28 10:04:33 +01:00
Hanno Becker
4f432ad44d Style: Don't use abbreviations in comments 2018-08-28 10:02:32 +01:00
Hanno Becker
b8f50147ee Add explicit MBEDTLS_DEBUG_C-guard around debugging code 2018-08-28 10:01:34 +01:00
Hanno Becker
f0da6670dc Style: Add braces around if-branch where else-branch has them 2018-08-28 09:55:10 +01:00
Hanno Becker
ecbdf1c048 Style: Correct indentation of debug msgs in mbedtls_ssl_write_record 2018-08-28 09:54:44 +01:00
Hanno Becker
3f7b973e32 Correct typo in mbedtls_ssl_flight_transmit() 2018-08-28 09:53:25 +01:00
Hanno Becker
6e12c1ea7d Enhance debugging output 2018-08-24 14:48:08 +01:00
Hanno Becker
0e96585bdd Merge branch 'datagram_packing' into message_reordering 2018-08-24 12:16:41 +01:00
Hanno Becker
1841b0a11c Rename ssl_conf_datagram_packing() to ssl_set_datagram_packing()
The naming convention is that functions of the form mbedtls_ssl_conf_xxx()
apply to the SSL configuration.
2018-08-24 11:13:57 +01:00
Hanno Becker
f4b010efc4 Limit MTU by maximum fragment length setting
By the standard (RFC 6066, Sect. 4), the Maximum Fragment Length (MFL)
extension limits the maximum record payload size, but not the maximum
datagram size. However, not inferring any limitations on the MTU when
setting the MFL means that a party has no means to dynamically inform
the peer about MTU limitations.

This commit changes the function ssl_get_remaining_payload_in_datagram()
to never return more than

MFL - { Total size of all records within the current datagram }

thereby limiting the MTU to MFL + { Maximum Record Expansion }.
2018-08-24 10:47:29 +01:00
Hanno Becker
283f5efe7d Buffering: Free future record epoch after each flight
The function ssl_free_buffered_record() frees a future epoch record, if
such is present. Previously, it was called in mbedtls_handshake_free(),
i.e. an unused buffered record would be cleared at the end of the handshake.
This commit moves the call to the function ssl_buffering_free() responsible
for freeing all buffering-related data, and which is called not only at
the end of the handshake, but at the end of every flight. In particular,
future record epochs won't be buffered across flight boundaries anymore,
and they shouldn't.
2018-08-24 09:34:47 +01:00
Hanno Becker
081bd81865 ssl_write_handshake_msg(): Always append CCS messages to flights
The previous code appended messages to flights only if their handshake type,
as derived from the first byte in the message, was different from
MBEDTLS_SSL_HS_HELLO_REQUEST. This check should only be performed
for handshake records, while CCS records should immediately be appended.
2018-08-23 19:22:26 +02:00
Hanno Becker
c83d2b3e09 ssl_write_handshake_msg(): Allow alert on client-side SSLv3
In SSLv3, the client sends a NoCertificate alert in response to
a CertificateRequest if it doesn't have a CRT. This previously
lead to failure in ssl_write_handshake_msg() which only accepted
handshake or CCS records.
2018-08-23 19:22:05 +02:00
Hanno Becker
b309b92ee8 ssl_buffering_free_slot(): Double-check validity of slot index 2018-08-23 13:18:05 +01:00
Hanno Becker
65dc885a3b Use size_t for msg_len argument in ssl_get_reassembly_buffer_size() 2018-08-23 09:40:49 +01:00
Hanno Becker
1b20e8e46e Merge branch 'datagram_packing' into message_reordering 2018-08-22 20:36:50 +01:00
Hanno Becker
554b0af195 Fix assertion in mbedtls_ssl_write_record() 2018-08-22 20:33:41 +01:00
Hanno Becker
7428d4fe87 Merge branch 'datagram_packing' into message_reordering 2018-08-22 16:16:59 +01:00
Hanno Becker
551835d5e7 ssl_write_handshake_msg(): Always append CCS messages to flights
The previous code appended messages to flights only if their handshake type,
as derived from the first byte in the message, was different from
MBEDTLS_SSL_HS_HELLO_REQUEST. This check should only be performed
for handshake records, while CCS records should immediately be appended.
2018-08-22 16:16:25 +01:00
Hanno Becker
2c98db2478 ssl_write_handshake_msg(): Allow alert on client-side SSLv3
In SSLv3, the client sends a NoCertificate alert in response to
a CertificateRequest if it doesn't have a CRT. This previously
lead to failure in ssl_write_handshake_msg() which only accepted
handshake or CCS records.
2018-08-22 16:05:47 +01:00
Hanno Becker
635313459f Merge branch 'datagram_packing' into message_reordering 2018-08-22 16:00:57 +01:00
Hanno Becker
11682ccc78 Uniformly treat MTU as size_t 2018-08-22 14:41:02 +01:00
Hanno Becker
3546201dbc Merge branch 'datagram_packing' into message_reordering 2018-08-22 10:25:40 +01:00
Hanno Becker
a67dee256d Merge branch 'iotssl-2402-basic-pmtu-adaptation' into datagram_packing 2018-08-22 10:06:38 +01:00
Manuel Pégourié-Gonnard
b8eec192f6 Implement PMTU auto-reduction in handshake 2018-08-22 10:50:30 +02:00
Hanno Becker
170e2d89da Merge branch 'iotssl-165-dtls-hs-fragmentation-new' into datagram_packing 2018-08-22 09:44:54 +01:00
Andres Amaya Garcia
a658d7dd9d Fix style for mbedtls_platform_gmtime() 2018-08-21 19:33:02 +01:00
Hanno Becker
aa71500173 Fix bug in SSL ticket implementation removing keys of age < 1s
Fixes #1968.
2018-08-21 17:48:52 +01:00
Hanno Becker
903ee3d363 Merge branch 'datagram_packing' into message_reordering 2018-08-21 17:24:17 +01:00
Hanno Becker
01315ea03a Account for future epoch records in the total buffering size
Previous commits introduced the field `total_bytes_buffered`
which is supposed to keep track of the cumulative size of
all heap allocated buffers used for the purpose of reassembly
and/or buffering of future messages.

However, the buffering of future epoch records were not reflected
in this field so far. This commit changes this, adding the length
of a future epoch record to `total_bytes_buffered` when it's buffered,
and subtracting it when it's freed.
2018-08-21 17:22:17 +01:00
Hanno Becker
a02b0b462d Add function making space for current message reassembly
This commit adds a static function ssl_buffer_make_space() which
takes a buffer size as an argument and attempts to free as many
future message bufffers as necessary to ensure that the desired
amount of buffering space is available without violating the
total buffering limit set by MBEDTLS_SSL_DTLS_MAX_BUFFERING.
2018-08-21 17:20:27 +01:00
Hanno Becker
e1801399a9 Add another debug message to ssl_buffer_message()
Report if there's not enough buffering space available to reassemble
the next expected incoming message.
2018-08-21 16:51:05 +01:00
Hanno Becker
55e9e2aa6b Free future buffers if next handshake messages can't be reassembled
If the next expected handshake message can't be reassembled because
buffered future messages have already used up too much of the available
space for buffering, free those future message buffers in order to
make space for the reassembly, starting with the handshake message
that's farthest in the future.
2018-08-21 16:24:30 +01:00
Hanno Becker
e605b19631 Add function to free a particular buffering slot
This commit adds a static function ssl_buffering_free_slot()
which allows to free a particular structure used to buffer
and/or reassembly some handshake message.
2018-08-21 16:24:27 +01:00
Hanno Becker
96a6c69d0c Correct bounds check in ssl_buffer_message()
The previous bounds check omitted the DTLS handshake header.
2018-08-21 16:11:09 +01:00
Hanno Becker
e0b150f96b Allow limiting the total amount of heap allocations for buffering
This commit introduces a compile time constant MBEDTLS_SSL_DTLS_MAX_BUFFERING
to mbedtls/config.h which allows the user to control the cumulative size of
all heap buffer allocated for the purpose of reassembling and buffering
handshake messages.

It is put to use by introducing a new field `total_bytes_buffered` to
the buffering substructure of `mbedtls_ssl_handshake_params` that keeps
track of the total size of heap allocated buffers for the purpose of
reassembly and buffering at any time. It is increased whenever a handshake
message is buffered or prepared for reassembly, and decreased when a
buffered or fully reassembled message is copied into the input buffer
and passed to the handshake logic layer.

This commit does not yet include future epoch record buffering into
account; this will be done in a subsequent commit.

Also, it is now conceivable that the reassembly of the next expected
handshake message fails because too much buffering space has already
been used up for future messages. This case currently leads to an
error, but instead, the stack should get rid of buffered messages
to be able to buffer the next one. This will need to be implemented
in one of the next commits.
2018-08-21 16:11:04 +01:00
Gilles Peskine
ed7da59798 ctr_drbg: add comments relating the code with the NIST specification 2018-08-21 17:55:46 +03:00
Hanno Becker
2a97b0e7a3 Introduce function to return size of buffer needed for reassembly
A previous commit introduced the function ssl_prepare_reassembly_buffer()
which took a message length and a boolean flag indicating if a reassembly
bit map was needed, and attempted to heap-allocate a buffer of sufficient
size to hold both the message, its header, and potentially the reassembly
bitmap.

A subsequent commit is going to introduce a limit on the amount of heap
allocations allowed for the purpose of buffering, and this change will
need to know the reassembly buffer size before attempting the allocation.

To this end, this commit changes ssl_prepare_reassembly_buffer() into
ssl_get_reassembly_buffer_size() which solely computes the reassembly
buffer size, and performing the heap allocation manually in
ssl_buffer_message().
2018-08-21 15:47:49 +01:00
Hanno Becker
e678eaa93e Reject invalid CCS records early
This commit moves the length and content check for CCS messages to
the function mbedtls_ssl_handle_message_type() which is called after
a record has been deprotected.

Previously, these checks were performed in the function
mbedtls_ssl_parse_change_cipher_spec(); however, now that
the arrival of out-of-order CCS messages is remembered
as a boolean flag, the check also has to happen when this
flag is set. Moving the length and content check to
mbedtls_ssl_handle_message_type() allows to treat both
checks uniformly.
2018-08-21 14:57:46 +01:00
Hanno Becker
47db877039 ssl_write_record: Consider setting flush variable only if unset 2018-08-21 13:32:13 +01:00
Hanno Becker
1f5a15d86d Check retval of remaining_payload_in_datagram in ssl_write_record() 2018-08-21 13:31:31 +01:00
Hanno Becker
ecff205548 Remove stray bracket if MBEDTLS_ZLIB_SUPPORT is defined 2018-08-21 13:20:00 +01:00
Manuel Pégourié-Gonnard
000281e07d Fix "unused parameter" warning in small configs 2018-08-21 11:20:58 +02:00
Hanno Becker
6aeaa05a95 Merge branch 'iotssl-165-dtls-hs-fragmentation-new' into datagram_packing 2018-08-20 12:53:37 +01:00
Hanno Becker
513815a38d Fix typo in debugging output 2018-08-20 11:56:09 +01:00
Hanno Becker
4cb782d2f6 Return from ssl_load_buffered_record early if no record is buffered 2018-08-20 11:19:05 +01:00
Manuel Pégourié-Gonnard
a1071a58a3 Compute record expansion at the right time
Depends on the current transform, which might change when retransmitting a
flight containing a Finished message, so compute it only after the transform
is swapped.
2018-08-20 11:56:14 +02:00
Manuel Pégourié-Gonnard
065a2a3472 Fix some typos and links in comments and doc 2018-08-20 11:09:26 +02:00
Hanno Becker
3a0aad1c9d Rename update_digest to update_hs_digest 2018-08-20 09:44:02 +01:00
Hanno Becker
4422bbb096 Whitespace fixes 2018-08-20 09:40:19 +01:00
Hanno Becker
e00ae375d3 Omit debug output in ssl_load_buffered_message outside a handshake 2018-08-20 09:39:42 +01:00
Manuel Pégourié-Gonnard
6e7aaca146 Move MTU setting to SSL context, not config
This setting belongs to the individual connection, not to a configuration
shared by many connections. (If a default value is desired, that can be handled
by the application code that calls mbedtls_ssl_set_mtu().)

There are at least two ways in which this matters:
- per-connection settings can be adjusted if MTU estimates become available
  during the lifetime of the connection
- it is at least conceivable that a server might recognize restricted clients
  based on range of IPs and immediately set a lower MTU for them. This is much
easier to do with a per-connection setting than by maintaining multiple
near-duplicated ssl_config objects that differ only by the MTU setting.
2018-08-20 10:37:23 +02:00
Hanno Becker
0d4b376ddf Return through cleanup section in ssl_load_buffered_message() 2018-08-20 09:36:59 +01:00
Ron Eldor
34b03ef78f Remove redundant else statement
Remove `else` statement, as it is redundant. resolves #1776
2018-08-20 10:39:27 +03:00
Hanno Becker
56d5eaa96c Mark SSL ctx unused in ssl_prepare_reassembly_buffer() if !DEBUG
The SSL context is passed to the reassembly preparation function
ssl_prepare_reassembly_buffer() solely for the purpose of allowing
debugging output. This commit marks the context as unused if
debugging is disabled (through !MBEDTLS_DEBUG_C).
2018-08-17 16:52:08 +01:00
Hanno Becker
b063a5ffad Update error codes 2018-08-17 16:52:08 +01:00
Hanno Becker
5f066e7aac Implement future record buffering
This commit implements the buffering of a record from the next epoch.

- The buffering substructure of mbedtls_ssl_handshake_params
  gets another field to hold a raw record (incl. header) from
  a future epoch.
- If ssl_parse_record_header() sees a record from the next epoch,
  it signals that it might be suitable for buffering by returning
  MBEDTLS_ERR_SSL_EARLY_MESSAGE.
- If ssl_get_next_record() finds this error code, it passes control
  to ssl_buffer_future_record() which may or may not decide to buffer
  the record; it does so if
  - a handshake is in progress,
  - the record is a handshake record
  - no record has already been buffered.
  If these conditions are met, the record is backed up in the
  aforementioned buffering substructure.
- If the current datagram is fully processed, ssl_load_buffered_record()
  is called to check if a record has been buffered, and if yes,
  if by now the its epoch is the current one; if yes, it copies
  the record into the (empty! otherwise, ssl_load_buffered_record()
  wouldn't have been called) input buffer.
2018-08-17 16:52:08 +01:00
Hanno Becker
37f9532081 Implement future message buffering and loading
This commit implements future handshake message buffering
and loading by implementing ssl_load_buffered_message()
and ssl_buffer_message().

Whenever a handshake message is received which is
- a future handshake message (i.e., the sequence number
  is larger than the next expected one), or which is
- a proper fragment of the next expected handshake message,
ssl_buffer_message() is called, which does the following:
- Ignore message if its sequence number is too far ahead
  of the next expected sequence number, as controlled by
  the macro constant MBEDTLS_SSL_MAX_BUFFERED_HS.
- Otherwise, check if buffering for the message with the
  respective sequence number has already commenced.
  - If not, allocate space to back up the message within
    the buffering substructure of mbedtls_ssl_handshake_params.
    If the message is a proper fragment, allocate additional
    space for a reassembly bitmap; if it is a full message,
    omit the bitmap. In any case, fall throuh to the next case.
  - If the message has already been buffered, check that
    the header is the same, and add the current fragment
    if the message is not yet complete (this excludes the
    case where a future message has been received in a single
    fragment, hence omitting the bitmap, and is afterwards
    also received as a series of proper fragments; in this
    case, the proper fragments will be ignored).

For loading buffered messages in ssl_load_buffered_message(),
the approach is the following:
- Check the first entry in the buffering window (the window
  is always based at the next expected handshake message).
  If buffering hasn't started or if reassembly is still
  in progress, ignore. If the next expected message has been
  fully received, copy it to the input buffer (which is empty,
  as ssl_load_buffered_message() is only called in this case).
2018-08-17 16:52:08 +01:00
Hanno Becker
6d97ef5a03 Use uniform treatment for future messages and proper HS fragments
This commit returns the error code MBEDTLS_ERR_SSL_EARLY_MESSAGE
for proper handshake fragments, forwarding their treatment to
the buffering function ssl_buffer_message(); currently, though,
this function does not yet buffer or reassembly HS messages, so:

! This commit temporarily disables support for handshake reassembly !
2018-08-17 16:52:08 +01:00
Hanno Becker
44650b7a74 Introduce function checking sanity of the DTLS HS header
This commit introduces helper functions
- ssl_get_hs_frag_len()
- ssl_get_hs_frag_off()
to parse the fragment length resp. fragment offset fields
in the handshake header.

Moreover, building on these helper functions, it adds a
function ssl_check_hs_header() checking the validity of
a DTLS handshake header with respect to the specification,
i.e. the indicated fragment must be a subrange of the total
handshake message, and the total handshake fragment length
(including header) must not exceed the record content size.

These checks were previously performed at a later stage during
ssl_reassemble_dtls_handshake().
2018-08-17 16:52:08 +01:00
Hanno Becker
12555c61d3 Introduce function to parse total handshake length
This commit introduces a static helper function ssl_get_hs_total_len()
parsing the total message length field in the handshake header, and
puts it to use in mbedtls_ssl_prepare_handshake_record().
2018-08-17 16:52:08 +01:00
Hanno Becker
0271f967d6 Introduce buffering structure for handshake messages
This commit introduces, but does not yet put to use, a sub-structure
of mbedtls_ssl_handshake_params::buffering that will be used for the
buffering and/or reassembly of handshake messages with handshake
sequence numbers that are greater or equal to the next expected
sequence number.
2018-08-17 16:52:08 +01:00
Hanno Becker
d7f8ae2508 Introduce sub-structure of ssl_handshake_params for buffering
This commit introduces a sub-structure `buffering` within
mbedtls_ssl_handshake_params that shall contain all data
related to the reassembly and/or buffering of handshake
messages.

Currently, only buffering of CCS messages is implemented,
so the only member of this struct is the previously introduced
`seen_ccs` field.
2018-08-17 16:52:08 +01:00
Hanno Becker
e25e3b7d96 Add function to check is HS msg is a proper fragment
This commit introduces a static function ssl_hs_is_proper_fragment()
to check if the current incoming handshake message is a proper fragment.
It is used within mbedtls_ssl_prepare_handshake_record() to decide whether
handshake reassembly through ssl_reassemble_dtls_handshake() is needed.

The commit changes the behavior of the library in the (unnatural)
situation where proper fragments for a handshake message are followed
by a non-fragmented version of the same message. In this case,
the previous code invoked the handshake reassembly routine
ssl_reassemble_dtls_handshake(), while with this commit, the full
handshake message is directly forwarded to the user, no altering
the handshake reassembly state -- in particular, not freeing it.
As a remedy, freeing of a potential handshake reassembly structure
is now done as part of the handshake update function
mbedtls_ssl_update_handshake_status().
2018-08-17 16:52:08 +01:00
Hanno Becker
d07df86871 Make allocation of reassembly bitmap optional
This commit adds a parameter to ssl_prepare_reassembly_buffer()
allowing to disable the allocation of space for a reassembly bitmap.
This will allow this function to be used for the allocation of buffers
for future handshake messages in case these need no fragmentation.
2018-08-17 16:52:08 +01:00
Hanno Becker
56e205e2c9 Prepare handshake reassembly in separate function
This commit moves the code-path preparing the handshake
reassembly buffer, consisting of header, message content,
and reassembly bitmap, to a separate function
ssl_prepare_reassembly_buffer().
2018-08-17 16:52:08 +01:00
Hanno Becker
9e1ec22c36 Return MBEDTLS_ERR_SSL_EARLY_MESSAGE for future HS messages
This leads future HS messages to traverse the buffering
function ssl_buffer_message(), which however doesn't do
anything at the moment for HS messages. Since the error
code MBEDTLS_ERR_SSL_EARLY_MESSAGE is afterwards remapped
to MBEDTLS_ERR_SSL_CONTINUE_PROCESSING -- which is what
was returned prior to this commit when receiving a future
handshake message -- this commit therefore does not yet
introduce any change in observable behavior.
2018-08-17 16:52:08 +01:00